Control and data transmission of existing general commercial unmanned aerial vehicles are mainly in a point-to-point transmission mode, which is divided into a ground end and an aerial vehicle end. The ground end mainly accomplishes remotely controlling an aerial vehicle, receiving and processing data returned by the aerial vehicle end and other work, while the aerial vehicle end mainly flies in accordance with an instruction from the ground end, and sends corresponding data to the ground end in accordance with the instruction from the ground end. The ground end and the aerial vehicle end form a point-to-point communication link, and stability and reliability of the communication link play an important part in safe and controllable flight of the aerial vehicle and data return.
In order to increase the stability and reliability of the communication link, it is necessary to increase communication system gain therebetween and maintain stability of the system gain as much as possible. A calculation formula of the system gain GSYS is as follows: GSYS=PT+GT+GR-PSEN, wherein PT is transmitted power, GT is the gain of a transmitting antenna, GR is the gain of a receiving antenna, and PSEN is receiving sensitivity of a receiving end.
At two ends of the unmanned aerial vehicle, the transmitted power and the receiving sensitivity will remain about the same, and the stability is relatively high. However, the actual relative gain of the receiving and transmitting antennas will vary with relative positions and orientations therebetween. Then, it can be seen from the aforementioned calculation formula of the system gain GSYS that, in order to maintain the stability of the system gain, the receiving and transmitting antennas need to be arranged in the maximum gain direction of the opposite side.
At present, in order to ensure alignment of the receiving and transmitting antennas, it is common to adopt a manner of a servo gimbal. Positions of the antennas are dynamically adjusted in accordance with the orientation of the opposite side or received signal strength, and there are such patents, domestic or foreign, covering this field. For example, a Chinese Patent of which the patent number is CN 202257283 U and the title of the disclosure is “AUTOMATIC TRACKING ANTENNA DEVICE AND MOBILE TERMINAL.” This Chinese Patent, on the basis of a servo gimbal and an electronic compass, automatically lets an antenna similar to a vehicle-mounted GPS to be aligned with the satellite. However, the structure of the automatic tracking antenna device of the Chinese Patent is relatively complicated, has a greater volume, and is not suitable for wireless communication in the field of unmanned aerial vehicles at all.